Fluid sampling devices, especially those used to collect aqueous samples from large bodies of fluids, for example, oceans and lakes, are well known. Such devices can be used to collect surface or near-surface physical, chemical, or biological (phytoplankton/zooplankton) samples in natural water bodies or industrial or man-made facilities (waste water ponds, water treatment plants, food processing plants, oxidation ponds, etc.) In particular, collection of water samples below the surface provides scientists the ability to obtain a sample at a known depth, retrieve the sample, and then perform analysis on the sample at a later point in time. By collecting a number of samples at various depths, a profile analysis of the body of fluid can be obtained. Unfortunately, existing sampling devices are cumbersome to use because their spring loaded closure designs require the use of a weighted messenger that must travel down a connecting line through the fluid and then trip a trigger that activates the closing mechanism. Such designs are known to frequently malfunction causing the device to close prematurely or to not close at all. Examples of these designs include three well known sampling bottles marketed under the names “Van Dorn,” “Niskin,” and “Kemmerer.” Each of these designs relies on a spring-loaded cover or cap that must be triggered when the device is lowered to a specified depth. Another serious drawback of these known sampling bottles is that they can only obtain one kind of sample, either “point” samples, i.e., obtain only a single sample at a single depth when in horizontal position (e.g. “Van Dorn”), or “vertically integrated” samples when in the vertical position A need therefore exists for a reliable, fool-proof sampling device that can take both point samples and a composite or integrated sample across a range of depths. I have now created such a design and a method of using it as will be described herein.